Apparatus and method protecting against attack by particulate chemical or biological agents

ABSTRACT

Potentially harmful particulate materials introduced into an airflow drawn into a structure&#39;s HVAC system are sensed by sensors provided on an intake fan and protective measures are taken in response to such sensed presence.

FIELD AND BACKGROUND OF INVENTION

The air intake components of traditional heating, ventilation, and air conditioning (HVAC) systems found in manufacturing and office facilities and in vehicles such as automobiles and train cars are vulnerable to biological or chemical agent attack. Some structures have outdoor air intake vents or portals at ground level, at mid-height, or on the roof of the structure. Depending upon the location of the actual air intake vents, these potential portals of attack are readily accessible. Biological agents, such as anthrax, small pox, SARS, influenza, TB, and other airborne infectious agents, can be readily introduced and disbursed throughout the buildings via their HVAC systems, as can harmful gases introduced as droplets of liquid.

Traditional HVAC systems are simple duct works with filtration that is not able to effectively remove these airborne agents. They were designed for maximum airflow efficiency, economy, and the removal of normal airborne particulates. Attempted protection by use of additional filtration such as high efficiency particulate (HEPA) is problematic as HEPA filters are fragile and must be frequently replaced. If used in an effort to intercept harmful materials, the discarded filters must be treated as hazardous waste if biological or toxic agents have been retained. Electrostatic filtration may be proposed as an alternative, using charged plates to remove particulates from the air stream and sequester them on the charge plates. These plates must be cleaned regularly to function. If infectious or toxic particulates are attracted, the cleaning process and disposal must account for the hazardous nature of the particulates trapped.

Note that none of these known filtration solutions are able to detect a sudden entrainment of particulate agents, nor are they able shut down and isolate the contaminated HVAC circuit, nor can they notify the proper building personal. Any effective solution must immediately detect the presence of particulate agents, immediately shut down the affected HVAC circuit, isolate that system, and notify the proper facilities management.

SUMMARY OF THE INVENTION

With the aforementioned problems in mind, it is one purpose of the present invention to immediately detect unusual particulate agents entrained into the supply air of HVAC systems, shut down the supply air fan, isolate the contaminated HVAC circuit from the rest of the building, and decontaminate the HVAC circuit affected. Additionally, the apparatus and method of this invention permits the extent of the penetration of the particulate agents within the HVAC system to be measured.

BRIEF DESCRIPTION OF DRAWINGS

Some of the purposes of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which:

FIG. 1 is a schematic elevation view of a system embodying the present invention; and

FIG. 2 is a schematic representation of a method of implementing the present invention.

DETAILED DESCRIPTION OF INVENTION

While the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which a preferred embodiment of the present invention is shown, it is to be understood at the outset of the description which follows that persons of skill in the appropriate arts may modify the invention here described while still achieving the favorable results of the invention. Accordingly, the description which follows is to be understood as being a broad, teaching disclosure directed to persons of skill in the appropriate arts, and not as limiting upon the present invention.

Areosolization devices have been demonstrated that are about the size of a 20 lb propane tank. HVAC supply air intake ducts typically have an open grill. The openings range from 3 feet to 10 feet in height. The grill (and possibly an additional coarse screen) would not hinder the entrance of biological agents or other harmful materials released from such a device either placed adjacent the supply air duct or within it should it be possible to easily remove the open grill.

In accordance with the present invention, an HVAC system (FIG. 1) supplying a structure 10 has an intake duct 11 with an air supply fan 12 drawing in air from the exterior of a conditioned area such as an office or other space. The fan 12 has a motor 14 and blades 15 bearing a sensor material 16 to detect significant changes in incoming supply air concentration of particulate matter. The sensor material 16 is also sometimes here referred to as a smart material due to its qualities and may be, for example only and not by way of limitation, applied films of piezoelectric materials, materials which form a capacitance or resistance couple, or materials which react with selected chemicals in such a way as to change electrical characteristics. Such materials may be applied in forms other than films, such as by depositing layers of materials by coating or the like. The material may be applied to surfaces other than the fan blades, although a recognized advantage of application to the blades is that rotation of the fan makes the sensor material self cleaning to a large degree.

The sensor material 16 on the fan blades 15 is coupled to an appropriate controller 18. The controller 18 is an electrical device with sufficient intelligence to monitor the change in electrical characteristics of the smart material 16. The controller 18 preferably can be set or programmed to distinguish levels of response by the smart material and initiate or trigger appropriate action as described more fully hereinafter. The controller is also coupled to the fan motor 14 and to a duct closure mechanism 19 located a known distance downstream from the fan. A signal sent from the controller when a pre-calibrated particulate concentration threshold change occurs at the smart material and fan blades is capable of shutting down the supply air intake fan assembly quickly by coupling an output signal from the controller to the fan motor 14 and to a fan brake 20 to turn off the fan assembly and actuate the fan brake, stopping further capture and infiltration of the questioned particulate matter.

The controller signals indicative of an inappropriate particulate material entering the HVAC system would also actuate the duct closure mechanisms 19A, 19B, thus sealing the contaminated portion of the HVAC duct work. The mechanisms 19A, 19B may be, for example only and not by way of limitation, shutters, an inflatable plug, or a swinging panel mounted in a normally withdrawn adjacent one side wall of the duct work. Measuring ports 21 located sequentially along the HVAC duct work downstream of the fan allow for sampling to determine the depth to which the potentially harmful particulates reached within the ductwork. This would allow an understanding of the extent of the HVAC ductwork that needed to be decontaminated. A secondary uncontaminated source of air 22 would then be released to slowly circulate in a countercurrent direction through the contaminated portion of the HVAC ductwork thoroughly mixing the release from a container 24 of a mist containing either biocidal chemicals to inactivate the biological agents or agglomerating agents to clump the particulates into non-respirable agglomerates (or both). The mist is collected via a chilling coil (or the like) 25 and the resulting condensate trapped into a holding vessel 26. This process can be repeated with a sequence or regimen of treatments or simply repeated using a single treatment.

Once the particulate contaminates have been collected into a holding vessel, the particulates can be further treated with heat, cold, ozonization, ultraviolet light, or chemical treatments to further render the condensate non-infectious and able to be disposed of safely.

The controller 18 also signals to an appropriate annunciator to signal to facility operators that the sensor material 16 has detected the presence of an invasive particulate material. The annunciator may be a system of lights or audible alarms located wherever appropriate to attract the attention of supervisory personnel to the occurrence.

These processes are illustrated by the flow chart of FIG. 2. In the chart, method steps are illustrated which comprise providing sensors for particulate material on the blades of an intake fan which impels a flow of air into the HVAC system of a structure; sensing with the sensors the presence of potentially harmful particulate material in an air flow impelled by the fan; and responding to the sensed presence of potentially harmful particulate material by stopping operation of the fan. The method steps, as illustrated, also comprise responding to the sensed presence of potentially harmful particulate material by stopping operation of the fan, blocking distribution of the impelled airflow downstream of the fan, trapping a contaminated portion of the impelled airflow; and decontaminating the trapped portion of the airflow.

The preferred embodiments described here can be used in transportation environments (trains, planes, subways, etc), mail rooms, schools, hospitals, and command and control rooms that have vulnerable ventilation systems.

In the drawings and specifications there has been set forth a preferred embodiment of the invention and, although specific terms are used, the description thus given uses terminology in a generic and descriptive sense only and not for purposes of limitation. 

1. Apparatus comprising: a duct; a fan impelling an air flow through the duct; a sensor material on said fan which detects the presence of potentially harmful particulate material in the air flow impelled by the fan; a duct closure mechanism located in the duct a distance downstream from the air flow impelled by the fan; a controller coupled to said sensor material, to said fan, and to the duct closure mechanism, wherein the controller stops said fan and actuates the duct closure mechanism to seal a contaminated portion of the duct in response to receiving signals from the sensor material indicating that the sensor material detected potentially harmful particulate material in the air flow impelled by the fan; and a plurality of measuring ports located downstream the fan for sampling to determine a depth to which the potentially harmful particulate material has reached within the duct.
 2. Apparatus according to claim 1 wherein said sensor material is a piezoelectric material.
 3. Apparatus according to claim 1 wherein said sensor material is an electrically resistive material.
 4. Apparatus according to claim 1 wherein said sensor material is an electrical capacitive material.
 5. Apparatus according to claim 1 wherein said sensor material is a chemically reactive material.
 6. Apparatus according to claim 1 further comprising a fan brake coupled to said fan and to said controller for quickly stopping impelling operation of said fan upon detection of potentially harmful particulate material in an air flow impelled by the fan.
 7. (canceled)
 8. Apparatus according to claim 1 further comprising a decontamination system coupled to said duct and to said controller which introduces into the portion of said duct between said fan and said duct closure mechanism a material effective to render harmless any potentially harmful particulate material impelled thereinto by the fan upon in response to the measuring ports detecting potentially harmful particulate material in the air flow impelled by the fan, and wherein the measuring ports detection determines an extent to which the duct needs to be decontaminated.
 9. Apparatus comprising: a structure; a fan impelling an air flow; ductwork within said structure communicating with said fan and distributing the impelled air flow within said structure; a sensor material on said fan which detects the presence of potentially harmful particulate material in the air flow impelled by the fan; a duct closure mechanism located in the ductwork a distance downstream from the air flow impelled by the fan; a controller coupled to said sensor material, to said fan, and to the duct closure mechanism, wherein the controller stops said fan and actuates the duct closure mechanism to seal a contaminated portion of the ductwork in response to receiving signals from the sensor material indicating that the sensor material detected potentially harmful particulate material in the air flow impelled by the fan; and a plurality of measuring ports located downstream the fan for sampling to determine a depth to which the potentially harmful particulate material has reached within the duct.
 10. Apparatus according to claim 9 further comprising a fan brake coupled to said fan and to said controller for quickly stopping impelling operation of said fan upon detection of potentially harmful particulate material in an air flow impelled by the fan.
 11. Apparatus according to claim 9 further comprising a decontamination system coupled to said ductwork and to said controller which introduces into the portion of said ductwork between said fan and said duct closure mechanism a material effective to render harmless any potentially harmful particulate material impelled thereinto by the fan in response to the measuring ports detecting potentially harmful particulate material in the air flow impelled by the fan, and wherein the measuring ports detection determines an extent to which the ductwork needs to be decontaminated.
 12. A method comprising: providing sensors for particulate material on the blades of an intake fan which impels a flow of air into a duct of a HVAC system; sensing with the sensors the presence of potentially harmful particulate material in the air flow impelled by the fan; responding to the sensed presence of potentially harmful particulate material by stopping operation of the fan and actuating a duct closure mechanism to seal a contaminated portion of the duct in response to receiving signals from the sensor material indicating that the sensor material detected potentially harmful particulate material in the air flow impelled by the fan; and sampling airflow with a plurality of measuring ports located downstream the fan to determine a depth to which the potentially harmful particulate material has reached within the duct.
 13. A method according to claim 12 wherein the provision of sensors comprises applying to the blades of an intake fan a material which responds electrically to the presence of potentially harmful particulate material.
 14. A method comprising: sensing at an airflow impelling fan the presence of potentially harmful particulate material in an air flow impelled by the fan through a duct; responding to the sensed presence of potentially harmful particulate material by stopping operation of the fan and actuating a duct closure mechanism to seal a contaminated portion of the duct in response to receiving signals from the sensor material indicating that the sensor material detected potentially harmful particulate material in the air flow impelled by the fan, wherein actuating the duct closure mechanism blocks distribution of the impelled airflow downstream of the fan, and trapping a contaminated portion of the impelled airflow; sampling the airflow with a plurality of measuring ports located downstream the fan to determine a depth to which the potentially harmful particulate material has reached within the duct decontaminating the trapped portion of the airflow in response to the measuring ports detecting potentially harmful particulate material in the airflow impelled by the fan, wherein the measuring ports detection determines an extent to which the duct needs to be decontaminated.
 15. (canceled)
 16. Apparatus according to claim 1, further comprising a secondary uncontaminated source of air released to circulate in the portion of the duct having the contaminated air flow in a counter current direction with respect to the air flow.
 17. Apparatus according to claim 16, further comprising: a container releasing an agent into the portion of the air duct to inactivate the contaminated air directed by the secondary uncontaminated source of air released in the counter current direction.
 18. Apparatus according to claim 17, further comprising a holding vessel to trap a mist containing the contaminated air mixed with the agent related into the portion of the air duct.
 19. (canceled)
 20. A method according to claim 12, further comprising releasing a secondary uncontaminated source of air released in the portion of the duct having the contaminated air flow in a counter current direction with respect to the air flow.
 21. A method according to claim 20, further comprising: releasing an agent from a container into the portion of the air duct to inactivate the contaminated air directed by the secondary uncontaminated source of air released in the counter current direction.
 22. A method according to claim 21, further comprising trapping in a holding vessel a mist containing the contaminated air mixed with the agent released into the portion of the air duct.
 23. The method of claim 1, wherein the plurality of measuring ports comprises at least three measuring ports located sequentially along the duct.
 24. The apparatus of claim 9, wherein the plurality of measuring ports comprises at least three measuring ports located sequentially along the ductwork.
 25. The method of claim 12, wherein the plurality of measuring ports comprises at least three measuring ports located sequentially along the duct.
 26. The method of claim 14, wherein the plurality of measuring ports comprises at least three measuring ports located sequentially along the duct. 